Field of the Invention
The present disclosure relates to data center networks. In particular, but not exclusively, the present disclosure relates to measures, including methods, systems and computer program products, for use in operating data center networks.
Description of the Related Technology
Consider the network architecture of a data center with virtual workloads (for example Virtual Machines, Linux Containers, etc.). A known topology is leaf-and-spine (also called a Clos network after Charles Cls), where each spine (or ‘end-of-row’) switch connects to each leaf switch, but leaf switches do not connect to one another, nor do spine switches connect to one another. Compute servers (or ‘hosts’ or ‘compute hosts’) for the virtual workloads only connect to leaf switches, as shown in the known data center network 100 of FIG. 1.
Features of this architecture include increased cross-connect bandwidth in the network for each additional spine switch, as well as redundancy against spine switch failures. Using Ethernet switches for the leaf and spine switches in this architecture can be problematic, however, because Ethernet does not tolerate loops in the topology. Running standard Spanning Tree Protocol (STP) on this topology will result in all but one of the spine switches being isolated.
Proprietary, vendor-specific systems exist, such as Multichassis Link Aggregation (MLAG), in which the spine switches are interconnected on a management network and exchange messages to allow them to present themselves as a single distributed switch to the leaves via Link Aggregation Control Protocol (LACP); thus the leaves can operate as if they have a single logical interface into the data center fabric.
Another method is to use Layer 3 networking approaches in order to enable the use of Layer 3 approaches. However, if Layer 3 technology is used to enable the compute servers to advertise their occupants, for example as described in U.S. patent application Ser. No. 14/231,616, the entirety of which is hereby incorporated by reference, there will be many more routes to be stored by each top-of-rack (or ‘leaf’) switch; this may exceed the route table capacity for these switches.
It would be desirable to have a solution to the above problems, for example one that employs open, industry standard protocols and which is easier to provision and diagnose.